Nano-level current-measuring device is important for the scanning tunneling microscope. The nano-ampere current measuring meter system based on high-precision amplifiers is mainly designed as two-stage amplifiers structure. Some removing interference ways of hardware are introduced in the design and facture of the PCB. In the current-measuring meter system, wavelet transform is adopted to decrease noise. The experiments show that, the measurement results of this device can be obtained to an accuracy of 1 nA, and the device can reduce some noise interference.