The paper presents an approach to fault extraction and test generation at RTL (Register Transfer Level). The proposed ATPG (Automatic Test Pattern Generation) is targeting to cover all the extracted faults rather than a specific fault, and based on simulation with unspecified inputs. It uses a request-echo strategy called X-Pulling to greatly reduce the unnecessary backtrack and implication, which makes the algorithm very efficient. Experimental results demonstrate that our approach is better than ARTIST [5] in three aspects: on average, the CPU time is shorter by three orders of magnitudes, the test length is shorter by 52% and the fault coverage is higher by 0.89%.