The urbanization process leads to many problems with resources and environment, and the problem of urban flooding is particularly prominent. The permeable floor can solve the problem of urban flooding from the perspective of ecology. Based on simulated rainfall, load test, freeze–thaw cycle test and so on, a comprehensive evaluation of permeable floor is carried out from the aspects of functional application, ecological effect and economy by means of gray analysis and AHP. It is showed that the permeable floor can reduce surface runoff and meet the functional requirements of floor. The evaluation of permeable floor mainly needs considering functional application and ecological effect index. The major factor of functional application is bearing capacity. The major factor of ecological effect is capability of conserving water. The major factor of economy is maintenance cost and durability. The gray evaluation result is between excellent and good when 4 level evaluation gray class which includes excellent, good, medium and poor is used. This study provides a reference for the solution of urban flooding and the evaluation of ecological floor.