The invention discloses a fluid system of a flow cytometer and a flow cytometric detection method. The fluid system comprises a sampling needle, a sampling needle cleaning device, a flowing chamber, a reaction tank, a hemolytic agent syringe, a sample syringe, a diluent syringe, a diluent bottle, a hemolytic agent bottle and a motor, wherein the sample syringe is respectively communicated with the sampling needle, the reaction tank, the flowing chamber, the sampling needle cleaning device and the diluent syringe, the diluent syringe is respectively communicated with the diluent bottle, the flowing chamber and the reaction tank, the hemolytic agent syringe is respectively communicated with the hemolytic agent bottle and the reaction tank, and the hemolytic agent syringe, the sample syringe and the diluent syringe are all driven and controlled by the motor. According to the invention, driving motors for a plurality of syringes are integrated into one, arrangement of the syringes satisfies moment balance, integral rigidity and inertia are improved, gap instability of the driving motor can be buffered, a more stationary sample flow can be obtained, and thus, detection precision of the flow cytometer is improved.