A novel method for determining weight of hybrid chirp in ultrashort laser pulses is presented based on asymmetry of Interferometric Autocorrelation (IAC) envelope, which is highly sensitive to weight of hybrid chirp and chirp magnitude. By analyzing and calculating the asymmetry of IAC envelope, the asymmetry envelope to determine weight of hybrid chirp, and center halfwidth of IAC envelope ratio and peak value of IAC envelope difference as a function of hybrid chirp for various weights were obtained. The theoretical analysis is supported by experimental ratio of IAC envelope and difference of IAC envelope. With this method, the hybrid chirp in ultrashort laser pulses was found and the linear and square chirp in chirped ultrashort laser pulse was measured 0.20 and 0.80, respectively. The measurement about weight of hybrid chirp in ultrashort laser pulses is realized.