The invention discloses a vaccination system for piglets. The vaccination system for the piglets comprises a leakage plate, water spraying devices, injection devices, photosensitive sensors and microcontrollers, wherein a plurality of through holes are formed in the circumference of the leakage plate and used for locating the positions of the piglets, and each through hole is used for locating the position of one piglet; the water spraying devices are arranged on the upper portion of the leakage plate and used for cleaning all the piglets and spraying vaccine medicaments, a water suction pump is arranged on each water spraying device, and each water suction pump is provided with a control switch used for starting and stopping the water suction pump; the injection devices are arranged on the through holes respectively, each injection device is used for vaccination of a single piglet, each injection device is provided with an air cylinder, and each air cylinder is provided with a relay used for controlling the starting and stopping of the corresponding air cylinder; the photosensitive sensors are arranged on the side walls of the through holes respectively and used for detecting the existence of the piglets above the through holes; the microcontrollers are used for receiving information transmitted by the photosensitive sensors and controlling the control switches and the relays to be started. By means of the vaccination system, vaccines can be more precisely and directly inoculated into the mucous membranes of the piglets.