High-pressure small-caliber no-load running check valve

The utility model discloses a high-pressure small-caliber no-load running check valve and belongs to the technical field of high-pressure valves. The check valve comprises a main valve body and is characterized in that the side of the main valve body is in clearance fit and connected with a side valve body, the upper side of the main valve body is attached and connected with a branch valve body, a rear positioning ring is fixed in the main valve body in a clearance fit mode, and a main valve clack penetrates through the rear positioning ring to be in clearance fit with the main valve body. A front positioning ring is fixed in the side valve body in a clearance fit mode, a positioning shaft is arranged on one side of the front positioning ring in an interference fit mode, the positioning shaft is in clearance fit with the main valve clack, a spring is arranged between the positioning shaft and the main valve clack, the two ends of the spring abut against the positioning shaft and the main valve clack respectiv