The invention relates to an assembly type anchor cable dynamometer and a use method. Three sets of measuring systems are distributed along the radial direction in an elastic body at a 120 degree angle. Each set of measuring system comprises two steel strings, an induction solenoid, an excitation solenoid and an electromagnetic converter apparatus. The assembly type anchor cable dynamometer is characterized in that the steel string is fixed in an arc-shaped elastic body, the steel strings, the induction solenoids and the electromagnetic converters in the elastic body are connected with an electronic display screen to form an enclosed circuit, induced-current in the induction solenoid enhances the magnetic field intensity of the excitation coil to maintain continuous vibration of the steel string, the electromagnetic converter apparatus converts mechanical frequency of the steel strings into electric signal frequency, detection data is displayed on the display screen, and a protective end cap is in threaded connection with the elastic body to prevent water and moisture. The assembly type anchor cable dynamometer is easy to install and dismount, the measuring structure is high in precision, and data can be acquired at any time. The assembly type anchor cable dynamometer is convenient for application of anchoring and monitoring engineering in the field of bridge, slope and water conservancy.