Frequency diverse array (FDA) has received much attention due to its range-dependent beampattern. The hybrid of FDA and multiple-input-multiple output (FDA-MIMO) radar is a promising technique, in which the multiple signal classification (MUSIC) algorithm is a popular choice for target localization, but rigorous resolution threshold analysis with noise perturbation consideration for FDA-MIMO radar is still missed. In this paper, we rigorously derive the resolution threshold of MUSIC algorithm for FDA-MIMO radar and examine the effects of modeling errors on the resolution threshold, along with the relations between range resolution and angle resolution.