The entry of outer space is one of the greatest science and technology achievements of mankind in the 20th century. It has been 50 years past since the first man-made satellite launched, and the aerospace exploration activities, including earth observation, manned space flight and deep-space exploration, have never been ceased. This paper retraces the space exploration history of the mankind, summarizes the major research progresses and achievements, analyzes the present development trends and our present tasks and problems, and finally raises several constructive suggestions and sketches out the blue prints of China's space exploration in the future.