The invention discloses a task scheduling method and system based on task stealing. The method comprises the steps that a task dependence graph is constructed, and a dependence point serves as a callback function to be registered into a callback container of a depended point; a lock-free double-end queue is allocated to threads in a thread pool respectively and is emptied, and root nodes are put at the bottoms of the lock-free double-end queues of the threads in a polling mode; if the lock-free double-end queues of the threads are not empty, the nodes are taken out of the bottoms of the lock-free double-end queues and are executed; if the lock-free double-end queues of the threads are empty, the nodes are stolen from the tops of the lock-free double-end queues of other threads, the stolen nodes are pressed into the bottoms of the lock-free double-end queues of the threads and are taken out for execution; after execution of all node tasks is completed, the in-degrees of the nodes in the task dependence graph are recovered to original values, and blockage to a main thread is ended. The task scheduling method and the system are oriented to large task-level parallel application programs, and the performance of traditional task-level parallel application programs can be effectively improved.