One-dimensional (1D) compressive sensing is often adopted in traditional sparse target detection of pulse Doppler radar. However, the 1D sparse target detection problem often requires large computational memory due to large measurement matrix. To solve this problem, this paper proposes a two-dimensional iterative hard thresholding algorithm (2D-IHT) for CS-based pulse Doppler radar to directly detect sparse targets. Compared with 1D CS frame algorithm, our proposed method can significantly reduce the memory requirement. Simulation results are provided to confirm the performance of the proposed method.