The invention discloses a measurement method of the water content of wet type clay sand based on pure resistance measurement, and relates to the field of casting and solves the problem that when the water content of the wet type sand is measured by a conventional resistance method, the testing precision is low because the resistance is influenced by capacitance parameters. The measurement method is realized through the following steps: (1) assembling a measurement device of the water content of the wet type clay sand based on the pure resistance measurement, wherein the measurement device consists of a resistance and moisture sensor, a signal conditioning unit, an exciting signal source, an A/D (Analog to Digital) conversion unit, a data communication unit and a computer; (2) assembling a voltage measurement circuit consisting of the resistance and moisture sensor, the signal conditioning unit and the exciting signal source; (3) measuring the resistance and the water content of the wet type clay sand by utilizing the measurement device for measuring the water content and the voltage measurement circuit. According to the method disclosed by the invention, through FFT (Fast Fourier Transform), extraction of a fundamental component of a sampling sequence and separation of a real part and a virtual part of the fundamental component, a value of the real part of the fundamental component related only to the resistance can be obtained, so that the resistance and the water content of the wet type sand can be precisely obtained.