A load-sensitive multi-path valve testing device includes the first, second, and third pressure sensors connected to the T, P, and LS ports of the load-sensitive multi-path valve; an oil outlet of an electronically controlled variable displacement pump connected to the P port of the load-sensitive multi-path valve via an oil supply pipeline; a first proportional relief valve and a first flow sensor connected on the oil supply pipeline; control oil ports of each commutation linkage respectively connected to a control oil source by two proportional pressure reducing valves; two working oil ports of each commutation linkage respectively connected to an oil tank by two proportional relief valves; flow sensors and pressure sensors arranged on two working oil ports of each commutation linkage. A testing method includes: using the device for pressure loss tests, micro-motion characteristic tests and flow saturation resistant characteristic tests.