A blend of bisphenol‐A based benzoxazine (BA‐a)/N, N′‐(2, 2, 4‐Trimethylhexane‐1, 6‐diyl) dimaleimide (TBMI) with the ratio of 1:1 was prepared and its curing behaviors were studied by differential scanning calorimetry (DSC), Fourier Transform Infrared (FTIR). The curing mechanism was proposed based on the semiquantitative analysis from FTIR spectra. The model compound was used to study the catalysis effect of BA‐a on the curing reaction of TBMI. It was found the curing reactions of BA‐a and TBMI not only proceeded simultaneously, but their coreactions also occurred. The research further indicated that negative oxygen ions from ring opening of benzoxazine mainly promoted the polymerization of maleimide groups, even though the amine group of benzoxazine had a positive effect on the reaction of maleimide groups. Besides, BA‐a and TBMI blends showed improved thermal properties based on the results from DMA and TGA.