The invention discloses a gap discharging test device for manually simulating strong wind and sand storm and a test method, wherein the test device comprises a flow field subsystem, an electric field subsystem and a measuring subsystem. In the test process, a sand sample is firstly placed in a sand sender; then the power frequency puncture voltage of the gap between electrodes is measured under the environment of clean air, next, a gap puncture discharging test is performed under the condition with different wind speeds and sand concentrations; a pressurizing method adopts a gradually pressurizing method, and a group of puncture voltages and concentration values are recorded after the puncturing happens; the pressurizing is repeated, each group of tests are repeated again and again to reduce the measuring error, and meanwhile, the sand flow temperature is recorded to be used as a reference. The invention can be used for performing the power frequency puncture of a gap on a transmission line under the environment of strong wind and sand storm and researching the discharging rule, has low cost, simple installation, good stability in the test process, easy operation, and the like.