Social Relationship But according to my experiece, it seems that people would like to use "sociable" to describe someone who has good 人脉. Only my opinion~

I agree with social relationship. "脉" is from traditional Chinese medicine, just a metaphor of things like network. So "人脉" means a network weaved by personal relationship.

general speaking, it means your social relationship. I think it's something about the quantity and job occupation of friends those who will help you in some way. In Chinese traditional belief, the things would be better if our friend can help us in decoration, buying sth; help our family mumber find a good job....almost everything in our daily life. So we alway said “人脉广”to describ those who can find a friend to help him or his other friends do the things they want to . Can you understand me? P.S.: Can you tell me my grammar mistake or how can I be understanded easily.

for me ,i will say interpersonal relationship or interpersonal skills

I think interpersonalship may be better. eg.cultivate one's interpersonalship