Abstract: Accurate skeletal age evaluation can assess the stage of individual development,and therefore provide the important reference for orthodontists to choose proper treatment timing and predict the growth potential. This paper explores three aspects,including the research status of the assessment of craniofacial growth and development,the influencing factors of skeletal age evaluation accuracy,and the improvement and development of skelatal age evaluation. The views are summarized as follows:1.The hand-wrist skeletal age, especially Fishman Skeletal Maturity Indicators (SMI),is organic, simple and reliable. The method of Cervical Vertebrae Maturation(CVM), especially Quantitative Cervical Vertebral Maturation (QCVM) which adapts to today's digital image trend, has attracted more and more attention with the obvious advantages, no need for additional x-ray exposure and easy to observe the mandibular growth peak. 2.The accuracy of skeletal age evaluation are affected by several factors,such as race、gender and evaluation methods. Therefore, it’s necessary to find the proper evaluation method for specific patients.3. Environmental factors can lead to abnormal bone development, especially the long-term disorders of biological clock,which influences the accuracy of skeletal age evaluation.It reminds us the importance of maintaining the normal biological rhythm. The new methods is proposed by regulating the biological clock to modify the abnormal craniofacial development and improve the assessment accuracy with skeletal age.

Key words: skeletal age, growth and development, skeletal maturity indicators, cervical vertebral maturation, biological clock