The invention discloses a field test method of influence on vertical bearing capacity of a pile foundation by a horizontal cyclic load. The method eliminates influence on test results by the foundation soil plastic deformation to the greatest extent through such methods as high-compressibility cushion layers at the bottoms of test piles and vertical cyclic loading; when the vertical displacement of a test pile foundation meets requirements, a final vertical loading test result is used as a reference parameter; then, a horizontal load is applied to the upper parts of the test piles for circulation according to the requirements; then, according to code requirements, the vertical loading is performed, and each stage of test data is recorded; and finally, twice vertical loading test pile testing results before and after horizontal loading are compared to calculate the influence on the vertical bearing capacity of the pile foundation by the horizontal cyclic load. The method particularly can effectively guide design and construction of such large engineering pile foundations as bridges and wharfs for such special geologies as coral reefs and diatomaceous earth in Southeast Asia, and ishigher in reference value.