To simplify the computational complexity of intra prediction mode selection for H.264/AVC, a fast intra prediction mode selection combination algorithm based on macroblock judgment is proposed in this study. This algorithm uses the three points gradient operator with a low-complexity to improve the edge direction histogram intra prediction mode selection algorithm (Pan algorithm), which obtains edge orientation vector by Sobel operator. Firstly, the MAD (Mean Absolute Difference) value is used to predict the threshold of the encoded macroblock type combined with QP. Then, the improved Pan algorithm is used to filter the pre-determined macroblock. Finally, an optimal prediction mode can be determined. The experimental results show that under the condition of six video sequences with all-I-frame coding, this algorithm reduces the coding time by about 72.4%. Compared with the Pan algorithm, the coding time is reduced by 28.6%, while the bit rate is increased by 4.21% and 1.8% respectively, and the PSNR is invariable.