High Frequency (HF) passive radar is a typical bistatic radar, and the modeling and simulation of sea clutter in bistatic radar are worth researching for HF passive radar. The paper first establishes a time-domain signal model of the first-order sea clutter in bistatic radar with a detailed derivation process. Then, based on the signal model, a new simulation method for the first-order sea clutter using band-pass filter and Hilbert transform is proposed. Simulation result verifies the validity of the proposed signal model and simulation method.