China’s traditional quantity-led demographic dividend is gradually disappearing. It is urgent to prolong the demographic dividend by improving the quality of the labor force

for which there is a serious shortage of skilled talents. At the same time

the labor-intensive platforms represented by takeaway and express delivery services begin to gather a large number of young and middle-aged labors. On the basis of literature review

this paper integrates qualitative and quantitative research methods

selects takeaway riders and couriers in Wuhan as survey objects

and obtains 810 valid questionnaires and 1891 minutes of interview recording. It finds that low threshold of the platforms

short pre-job training and low risk in quitting create the external conditions with low job-seeking cost for workers

while high salary and flexible working style meet workers’ individual pursuit of a good career. External conditions and internal motivation together lead to the career choice of "online contract workers" .