Abstract: The propagation and evolution characteristics of blast waves in confined spaces are complicated due to the constraint of the surrounding walls, by which the enhanced reflected shock waves will cause more serious damage to the internal structures, facilities and personnel. In order to investigate the characteristics of explosions in confined spaces, an in-house high-resolution hydrocode was developed in this present work. The third-order WENO finite difference scheme (weighted essentially non-oscillation scheme) was implemented in the code to capture the shock waves generated by cylindrical explosives. The Sod shock tube problem, interacting blast wave problem and blast in air problem were simulated to validate the code. The validated code was then used to simulate the blast waves generated by condensed explosives in closed, vented and connected spaces. The propagation of blast waves and the characteristics of blast load were subsequently investigated. The developed code appears to accurately predict the process of explosions in confined spaces. This high-resolution hydrocode can be used to study the propagation paths of blast waves in complicated spaces and evaluate the internal blast load, which can provide reliable input for the design of explosion-resistant structures.