Nowadays, proteomics focuses on quantitative analysis rather than qualitative. In the field of quantitative proteomics, Isobaric tags for relative and absolute quantitation (iTRAQ) is one of the most widely used techniques. The advantage of iTRAQ is high throughput, high stability and free of the restriction of sample property. iTRAQ is suitable for almost all kinds of samples, and up to 8 samples can be analyzed simultaneously by commercially available kit. Along with the development of techniques, more and more mass spectrometry (MS) platforms are used in iTRAQ experiments and the accuracy of iTRAQ has been improved. iTRAQ has been applied to studies of microorganism, animal, plant, medical and protein post-translational modification. Here we review the recent progress in the development of iTRAQ and its applications in quantitative proteomics.