Abstract: The generation of sub-cycle femtosecond laser pulses is usually achieved by spectral broadening and compression of tens of femtosecond laser pulses using hollow-core fibers or nonlinear solid-state media. However, the current industrial femtosecond laser sources with high stability and relatively low cost typically have pulse durations in the hundreds of femtoseconds range. Therefore, the spectral broadening and compression of hundred-femtosecond laser pulses have great practical significance. A titanium sapphire laser with a pulse width of 145 fs was focused, and the two-stage spectral broadening and pulse width compression were achieved using solid thin-film assemblies and chirped mirrors. Pulse waveform and pulse width measurements were conducted using transient grating frequency-resolved optical gating (TG-FROG) method. Ultimately, a laser pulse output with a duration of 7.5 fs was successfully obtained, achieving a compression factor of 19, with an energy conversion efficiency exceeding 81%. The repeatability of pulse width measurements before and after compression is 2.4% and 3.4%, respectively. The research results provide reference ideas for the compression of hundred-femtosecond industrial femtosecond laser sources towards sub-cycle femtosecond lasers.