A new, rapid, simple, accurate analysis method to detect calcium in foods was established. Some oily nuts were selected as samples, dissolved by microwave, and detected by ion selective electrode and standard concentration direct reading method. The results indicated that the conversion coefficient of calcium electrode was 98.61% and the relative standard deviation was less than 4%. The method is rapid, simple, direct reading, low cost and less sample consumption. It provides a new analytical technique for the determination of calcium in foods. The method has a strong creative and application value.