On the one hand, ethylene glycol, linear low density polyethylene (LLDPE), polypropylene (PP), polyvinyl chloride (PVC) and other listed products on the exchange of Dashang are all in the olefin industrial chain, and they compete with the industrial chain to some extent, and there is a strong and weak price relationship. On the other hand, the varieties listed on other exchanges, such as crude oil (SC), methanol (MA), purified terephthalic acid (PTA), cotton yarn and cotton (CF), belong to the middle and lower reaches of the industrial chain, and there is cost support between them.