The invention provides a drop hammer height adjusting device for high strain detection of a pile foundation, the device comprises: a cross beam support frame, an avoiding hole is opened in the middle of the surface of the cross beam support; a track extending through the avoiding hole, a tooth group is arranged on each of two surfaces of the track bar, and abutting sliding blocks are further arranged at two sides of the track bar. The abutting sliding block is cooperated with the tooth group to limit the position of the track bar. The invention overcomes the significant disadvantages of the existing detection devices, the efficiency of obtaining qualified test signals is improved by the rapid and accurate height adjustment and test, and the precision and efficiency of high strain detection of a foundation pile are greatly improved.