Abstract:The elimination of 'whole airspace effect' is a difficult problem in electromagnetic exploration. Experts both in China and abroad have tried to solve this problem from such aspects as basic principle, data-processing and traverse employment; nevertheless, there exist problems like harsh condition for seeking solution, complicated calculation, difficulty in realizing technical aim and high cost. This paper puts forward a new train of thought in which shielding apparatus is employed to directly eliminate the whole airspace effect so as to approach ground-style survey. The corresponding device is developed, and the application method and examples are given. Practice shows that the result is satisfactory.