This paper presents Unisolver, a general-purpose neural network-based PDE solver capable of solving a wide range of partial differential equations (PDEs). Existing neural network-based PDE solvers are limited to specific PDEs or a limited set of coefficients, resulting in poor generalization performance. Unisolver leverages the mathematical structure of PDE solutions to flexibly integrate PDE components, such as equation symbols and boundary conditions, into a transformer model as domain- and point-specific conditions. Trained on diverse data, Unisolver demonstrates state-of-the-art performance and generalization capabilities on three large-scale benchmarks. The source code is available on GitHub.