To solve the technical difficulties in the collaborative design of wide range, high accuracy, and smooth operation of domestic reciprocating piston flowmeters, a four piston linkage kinematic model based on crank slider mechanism was established, and the piston motion law and dynamic characteristics were systematically analyzed; By utilizing gap optimization control technology, the influence mechanism of motion pair gap on piston resistance and leakage was studied, breaking through the key technical difficulties of gap matching and dynamic sealing under high-precision working conditions, and ultimately achieving the structural optimization design of a four piston linkage piston flowmeter. Experimental tests have shown that the flow measurement range of the developed prototype can reach (5-10000) mL/min, and the accuracy within a 200:1 range can reach ± 0.54%. It can effectively meet the technical requirements of industrial sites for wide range and high-precision flow measurement, and has good engineering applicability. It plays a technical support role in promoting independent innovation and domestic substitution in the field of high-end flow measurement instruments in China.