We theoretically present a passive method for intra-cavity spectral shaping in a broadband Ti : S regenerative amplifier on optical rotatory dispersion (ORD). Besides a polarization-dependent Ti : S gain crystal, implementing the method requires a broadband half-wave plate and a wedge pair made of an optical rotator crystal for an adjustable ORD. Our calculations show inducing proper ORD allows the amplifier to boost an 800 nm pulse from sub-nJ up to 3.18 mJ with a bandwidth of 94.5 nm without peak wavelength shift or spectral narrowing. For a certain ORD, this method allows us to get tunable broadband amplification with almost constant output pulse energy by simply rotating the half-wave plate. In spite of its flexibility in controlling the output spectrum of the amplifier, this method is very simple to align.