This paper presents a monolithic integration of piezoresistive micro-cantilevers with CMOS (Complementary Metal Oxide Semiconductor) analog amplifier and digital multiplexer based on the techniques of SOI (Silicon On Insulator) CMOS and MEMS (Micro Electronic Mechanical System). The three modules, signal detection, signal selection and signal amplification, of the design are proposed step by step. Then, SOI-CMOS-PD (Partially Depleted) is compared with SOI-CMOS-FD (Fully Depleted) to ensure its advantages in analog IC. And the post-CMOS process is designed as manufacture solution. Finally, simulations and test results are presented to prove the availability of the whole project.