The conventional search and medical rescue methods for shipwrecks at sea have the problem of low coverage. In order to improve this issue, this study designed a probability density function-based method for assisting decision-making in the search and medical rescue of shipwrecks at sea. First, extract the disturbance factors of maritime search and adjust the initial plan. Then, divide the search and rescue task stages and enter the search and rescue area according to the planned shortest path. Finally, construct a probability density function for the location of the target in distress, clarify the drift trajectory of the target of the shipwrecked vessel, and achieve auxiliary decision-making for seeking medical assistance considering safety. In the experiment, scenario experiments were designed in real sea areas, and the results showed that the average coverage rate of the search and medical assistance of this method was 76.03%, indicating that the method effectively achieved the design expectations.