A content-adaptive Distortion-Quantization (D-Q) model for intra coding of H.264/AVC is proposed in this research. A single-parameter Distortion- Quantization (D-Q) relationship is derived for predicting the coding performance associated with the Quantization Parameter (QP). The content complexity of a macroblock (MB), which is evaluated by using the Sum of Absolute Transformed Difference (SATD), will be employed to determine the model parameter so that a suitable QP can be assigned. In order to acquire a video with more consistent quality, we propose two schemes, i.e. the two-pass method and the single-pass scheme with self adaption. In the two-pass scheme, the resulting frame quality after the first encoding pass using the initial QP is evaluated and a refining factor will be computed to determine a more appropriate QP. In the single-pass adaptive scheme, the adjustment is applied by referencing the model accuracy in the previous frame. The experimental results show that the assigned QP can effectively help to achieve the targeted frame quality in the H.264/AVC intra coding.