thanks for you reply!!
I changed into this:
	  cv::Mat one_mat(heatMapsTensor.size(1), heatMapsTensor.size(2), CV_32FC1);
	  std::memcpy(one_mat.data, one_heat_map.data_ptr(), sizeof(float) * one_heat_map.numel());

This time, the cv::Mat values seems normal, but result still not right.
what I want , is convert a tensor in multi dimension: [19, 32, 46] into a vector, length is 19, and every member in vetor is cv::Mat with size of 32,46.
Now, dims is right, the issue is the value converted into cv::Mat is always not right, it is not the same value in tensor.