A human skin water and oil analysis circuit, the human skin water and oil analysis circuit comprising a water and oil detection module (110) and a single chip microcomputer (120). The water and oil detection module (110) is used to receive a square wave signal, and use the square wave signal as an excitation signal to detect the percentages of water and oil on the human skin, and obtain a voltage signal capable of reflecting data of the percentages on water and oil of the human skin; the single chip microcomputer (120) is used to perform analog-to-digital conversion on the voltage signal obtained by the water and oil detection module (110), and send the voltage signal that has been converted from analog to digital to an external data processing device such that the external data processing device performs data analysis on the voltage signal so as to detect the data of the percentages of water and oil on the human skin. A skin testing instrument, comprising the human skin water and oil analysis circuit. By means of the foregoing manner, the accuracy of tested data of the percentages of water and oil in the human skin test may be increased.