The requirement for the reliability of the chip in the area of biochemical analysis is very strict.In order to ensure the precision of complex biochemical experimental analysis results, the contamination should be cleaned.In this paper,the online contamination removal based on Maxmin ant colony algorithm has been proposed to realize reducing the time of washing contamination.Establishing MTSP model for digital microfluidic biochips contamination,establishing tabu judgement strategy based on fluid and time constraints and the selection strategy of the ant colony algorithm to achieve the purpose of optimizing the path planning of wash droplet and cleaning up contamination.The experiment results show that the scheme can reduce the time of clearning contamination,comparing with MCC algorithm it can reduce the used cells effectively.