The invention discloses a micro dynamic probing instrument and a test method . The dynamic probing instrument comprises a probe, a probing rod, a hammer base, a guide rod, a replaceable drop hammer and a cover piece; the method comprises following steps: a test mold is used for preparing a sample, the surface of the sample is leveled, and the sample height is recorded; according to the hardness degree of the tested sample, the proper drop hammer is selected and is loaded in the probing rod; a round conical head is aligned with the surface of a soil sample to be detected, and it is ensured that the probing rod is perpendicular to the surface of the soil sample; the drop hammer is lifted to an upper baffle, and is loosened so as to freely drop; when the probing rod enters the sample by 20 mm, the probing rod is taken out, the knocking number of the drop hammer at the moment is recorded, the test is finished, and instrument devices are arranged; a parallel test is carried out; test data are arranged and analyzed. The dynamic probing instrument is small in size, and convenient to carry, operation is easy, a test result can be rapidly obtained, under the site test condition, multiple sets of tests can be achieved, the test error is reduced, and the test precision is improved.