This paper is an investigation of 62 human fetuses of different age groups between the 10th week-38th week of fetal life. It aims at the assurance of the time of the first appearance of the taeniae and haustra and the discussion on the cause of the formation of the haustra. The haustra of the human colon first appeared at the 56 mm. CR stage (the end of 10 th week). The taenia mesocolica appeared much earlier than the other ones. We found that the taenia mesocolica could be seen at the end of 10th week of fetal life, while the other two taeniae at the 68 mm. CR stage, i. e. one week later than the first. The thickness of the circular muscle layer in the haustra cleft and of the longitudinal muscle layer of the taenia was increased along with the fetal age. The number and the depth of the haustra cleft were also in proportion with the increase of the fetal life. It is reasonable to suggest that the uneven distribution of the circular muscle layer of the haustra, especially the thickness of the circular muscle layer in the site of the cleft plays an important role in the formation of the haustra. The muscle fibres of the inner longitudinal muscle which interlace with the circular muscle are the morphological basis for the continuous presence of the haustra and constant in position. The fact that the haustra and taenia of the human colon appeared at about the same time leads us to doubt the truth of the traditional saying——the formation of the haustra is due to the uneven developmental rate of the longitudinal muscle and the length of the colon. The formation of the haustra has intimate relation with the kinds of food which one takes in.