Calcium formate is used to increase weight, and calcium formate is used as a feed additive for piglets to promote appetite and reduce diarrhea. Calcium formate is added to the feed in a neutral form. After the piglets are fed, the biochemical action of the digestive tract will release a trace of formic acid, thereby reducing the pH value of the gastrointestinal tract. It promotes the growth of beneficial bacteria in the digestive tract and reduces the symptoms of piglets. In the first few weeks after weaning, the addition of 1.5% calcium formate to the feed can increase the growth rate of piglets by more than 12% and increase the feed conversion rate by 4%.