A low noise current amplifier based on the cryogenic current comparator (CCC) is designed and fabricated, which can be used for precision measurement of pA level weak current. The amplifier consists of superconducting proportional coils with a maximum turn ratio of 2 000 ∶ 1, a DC-superconducting quantum interference device and a superconducting shield. The equivalent input current noise, current sensitivity and feedback loop model of the amplifier are established. On this basis, the methods to reduce the amplifier noise and improve the amplifier sensitivity are proposed. Experimental results show that the coupling coefficient between CCC superconducting proportional coils and pick-up coil with 12 turns is 0. 61. When the CCC current amplification ratio is 2 000 ∶ 1, the equivalent input current noise of the amplifier is 30 fA/ Hz 0. 5 at 1 Hz. The current sensitivity is 4. 71 nA/ Φ0 and the performance of the amplifier has been evaluated in the test of peak to peak 6 pA square wave current.