The invention discloses a low power consumption weak signal amplification shaping circuit, which relates to the technology of integrated circuits and comprises a reference source circuit, an amplification circuit and a Schmitt trigger shaping circuit, wherein the amplification circuit consists of an opa (optoelectronic pulse amplifier), two capacitors and two PMOS (positive channel metal oxide semiconductor) tubes, the Schmitt trigger shaping circuit consists of three PMOS tubes, three NMOS (N-Metal-Oxide-Semiconductor) tubes, an inverter INV and an SR (Synchronous Reset) trigger, and the reference source circuit consists of two PMOS tubes, two NMOS tubes and three resistors. In the invention, a flip threshold controllable mixed mode Schmitt trigger is adopted, and three equally-spaced negative temperature coefficient reference voltage offset pre-amplification circuits and Schmitt triggers are used so as to ensure the circuit of higher precision under any PVT (process verification test) conditions. The circuit disclosed by the invention has lower power consumption, and simultaneously has higher PVT change resisting capacity.