The present invention provides a femtosecond pulse laser modulator and a miniature two-photon microscopic imaging device. The femtosecond pulse laser modulator includes a negative dispersion light path and a positive dispersion light path, wherein the negative dispersion light path includes a laser input fiber, which is configured to transmit laser compensated for through prechirp； the positive dispersion light path is located between a femtosecond pulse laser and the negative dispersion light path, and is configured to compensate for, through prechirp, negative dispersion of the laser produced in the laser input fiber. The femtosecond laser modulator provided in the present invention provides distortion-free transmission for the femtosecond pulse laser with a center wavelength in 920 nm, and effectively excites commonly used biological indicators. The miniature two-photon microscopic imaging device including this femtosecond laser modulator has high speeds in test and application, with high resolution, and is capable of solving the problem of imaging single dendritic spines in a freely behaving animal.
