In this study, a case of acute cattle death was investigated. The pathogen was identified, and its molecular characteristics and vector were analysed. This study provides a reference for the prevention and control of babesiosis and the healthy breeding of cattle. In this study, unengorged and engorged Rhipicephalus microplus ticks were collected from the Chongqing area. The unengorged ticks were cultured on cattle under laboratory conditions, and the engorged ticks were cultured to lay eggs. In the process, the cattle suddenly died at 12 days from the bite of an unengorged R. microplus tick. In addition, the larvae hatched from R. microplus eggs, which were cultured on the other cattle, and the experimental cattle died in approximately 14 days. Blood was collected from a second dying and stored at 4 ℃ for one week. Two millilitres of anticoagulated blood was injected subcutaneously into the third cow without piriformis infection. On the fourth day, the body temperature rose to 41 ℃ with slight lymphadenopathy. On the fifth day, the cow suddenly fell and died approximately 4 hours later. DNA was extracted from the blood of all dead cattle and amplified by PCR with piriformis universal primers. The results showed that the cattle were infected with Babesia bovis. The phylogenetic tree based on 18S rRNA showed that the Chongqing strain of B. bovis, which caused the death of cattle, was closely related to the Yunnan strain in China and had the same taxonomic status as the Spanish strain. This case report will draw people's attention to B. bovis once again, and positive control measures should be taken to reduce the losses of farmers to achieve the goal of healthy breeding.