We present a novel, accurate, full-filed, dynamic quantitative phase imaging (QPI) technique by using multi-wavelength multiplexing and multi-plane iterative phase retrieval algorithm. In our method, a liquid crystal spatial light modulator is employed to flexibly generate multiple defocus intensity images at once, using its adjustable phase modulation characteristics of different wavelengths. Then these images contained at different wavelengths are captured by two color cameras with single exposure. To achieve accurate QPI, a multi-plane iterative phase reconstruction algorithm is also proposed based on transport of intensity equation (TIE). Finally, with these multiple defocus images, an accurate dynamic phase result can be provided by our approach. In addition, the errors caused by color coupling of color camera and chromatic aberration of the optical system are both analyzed and effectively compensated. Experiments conducted on the phase plate, living human colorectal cancer cells and human red blood cells well demonstrate the accuracy, dynamic measurement ability and flexibility of our method.