Effects of annealing on crystallization and crystal transition of nylon 1111 were investigated by wide angle X-ray diffractions (WAXD). The results indicate that the γ-form crystal is produced when the sample is annealed below 145 ℃, while the α-form crystal is generated above 145 ℃. Annealing time has nothing to do with the crystal transition. Melting behaviors of Nylon 1111 were studied by differential scanning calorimetry (DSC). The results show that there is only one endothermic peak for the different crystal phases obtained by annealing above and below 150 ℃. And the degree of crystallinity of Nylon 1111 will increase with increasing annealing time.