Abstract: In order to preliminary find out the infection of Cryptosporidium canis in dogs in Harbin, 2 000 fecal samples of dogs were collected from pet hospital, the pet market and animal clinic in the city from January to December 2018. The Cryptosporidium oocysts in the faecal samples was examined and identified according to the size and morphology of the oocysts. According to the identification results, Excel software was used to sort out and analyze the infection of Cryptosporidium canis at different survey points, in different ages and in different seasons in dogs. The results showed that the oocysts obtained were Cryptosporidium canis oocysts. Cryptosporidium canis oocysts were detected in 430 fecal samples, and the infection rate was 21.50%（430/2 000）. The infection rates of pet hospitals, pet markets and animal clinics at different survey areas were 36.51%, 17.33% and 11.29%, respectively. The infection rates of dogs younger than 4 months, 4-8 months, 8-12 months and over 1 year old were 36.59%, 24.14%, 28.21% and 10.99%, respectively. The infection rates were also different in different seasons, including 24.05% in spring, 28.82% in summer, 16.98% in autumn and 11.62% in winter. The results suggested that the infection of Cryptosporidium canis was different in age and seasonality, and the infection rate was high due to poor feeding and management conditions.