Prediction of cracking is greatly important when evaluating the stability and safety of underground engineering projects. In this paper, 3D-printed samples with a single non-straight fissure are uniaxially compressed, and the effects of the inclination angle and effective curvature on the cracking are observed. A simplified approach is proposed for the determination of tip cracking and non-tip cracking of the non-straight fissure. The accuracy of the prediction is validated by the uniaxial tests. The results show that the cracking behavior of non-straight fissures is different from that of straight fissures with respect to the occurrence of non-tip cracking. Moreover, cracking is significantly influenced by the geometric parameters of the non-straight fissure. In addition, the proposed approach can be utilized to predict the cracking of non-straight fissures with acceptable accuracy.