Abstract: Multi-input multi-output (MIMO) radar is a new radar technique developed recently. On transmitting, each channel radiates a unique and orthogonally coded waveform. On receiving, the return signals are processed through a bank of matched filters to separate each transmitted signal. Hence, the orthogonal performance between signals is crucial for implementing MIMO radar system. In this paper, the cross-ambiguity of OFD-LFM (orthogonal frequency division linear frequency modulation)signals is analyzed. The location and level of the cross-correlation peaks are investigated. The relation between the parameters that minimize the cross-correlation peaks of MIMO signals is derived. The simulation validates the correctness of the proposed theoretical analysis.