This study was investigated to research the quality characteristics of feed-grade monocalcium phosphate (MCP) produced by three different production processes (calcium precipitation method, calcium+sodium precipitation method and steam method), and provided an experimental basis for the formulation of the national mandatory standard and the rational use of MCP. The MCP samples were collected from ten manufacturers from the representative areas of China, and the contents of free water, crystal water, calcium, total phosphorus and water-soluble phosphorus, the mass ratio of calcium to phosphorus, fineness, the number of crystal water and pH were detected for comparing differences among the three different production processes and among the samples from the nine manufacturers which used the calcium precipitation method and calcium+sodium precipitation method. The results showed as follows: 1) the comparison of different production processes, the pH of steam method was significantly higher than that of calcium precipitation method and calcium+sodium precipitation method (P<0.05), and the pH of calcium precipitation method was significantly higher than that of calcium+sodium precipitation method (P<0.05). The contents of free water, crystal water, calcium, total phosphorus and water-soluble phosphorus, the mass ratio of calcium to phosphorus and the number of crystal water of the three production processes were not significantly different (P>0.05). The contents of 0.50 and 0.40 mm fineness of steam method were significantly higher than those of calcium+sodium precipitation method (P<0.05). 2) The comparison of different manufacturers, the contents of free water of all samples were significantly different (P<0.05), the content of crystal water and the number of crystal water of sample 4 were significantly lower than those of other samples (P<0.05), and there was no significant difference in pH between sample 5 and samples 8 and 9 (P>0.05), but sample 5 was significantly lower than other samples (P<0.05); all of the fineness of sample 4 were significantly lower than those of other samples (P<0.05); the content of calcium of samples 1 and 6 was significantly higher than that of other samples (P<0.05), and the content of total phosphorus of sample 9 was significantly higher than that of samples 1, 2, 4, 5, 6 and 7 (P<0.05); the content of water-soluble phosphorus of sample 5 was significantly higher than that of other samples (P<0.05), and the content of water-soluble phosphorus of sample 1 was significantly lower than that of other samples (P<0.05); the mass ratio of calcium to phosphorus of sample 1 was significantly higher than that of other samples (P<0.05), and that of sample 9 was significantly lower than that of other samples (P<0.05). It is concluded that in the three production processes, the contents of water-soluble phosphorus, free water and crystal water, the number of crystal water and pH of steam method are the highest; the contents of water-soluble phosphorus and crystal water and the number of crystal water of calcium precipitation method are the lowest, but the mass ratio of calcium to phosphorus is the highest; the contents of total phosphorus and all fineness of calcium+sodium precipitation method are the highest. Because of the different manufacturers and production processes, there are some differences in the quality indicators of MCP. In addition to the quality indicators prescribed by national standards, we should also consider crystal water content, the number of crystal water and mass ratio of calcium to phosphorus, and also propose to reduce the requirements of fineness.