According to the analysis of PTA price changes in recent years, PTA price has two decisive factors. The first is supply and demand. In the case of imbalance between supply and demand, the relationship between supply and demand plays a decisive role in price; The second is cost-driven. Under the market situation of oil price fluctuation, the upstream cost transfer effect of petroleum-based petrochemical industry is remarkable. The price of PTA is largely controlled by raw material PX and oil price, especially when the price of PTA is quite close to the cost or even upside down, the force of raw material price change is very obvious. These two factors are often intertwined in reality. For example, the rise in crude oil prices in recent years will generally be quickly reflected in the price of PX (para-xylene), leading to the rise in PTA prices. Under the premise that downstream chemical fiber enterprises and textile enterprises can bear it, this cost change can be effectively transmitted downwards. But to a certain extent, once the PTA price is too high, which exceeds the market affordability of downstream enterprises, it will lead to poor sales of downstream products, decreased production and sales of polyester products, and increased inventory, which will follow. The polyester factory can't pass on the high cost at all, and the polyester will inevitably have a large-scale negative growth, and the reaction force of the downstream industrial chain will be transmitted to the upstream, thus reducing the market demand for PTA. Therefore, PTA market is not a simple cost-driven market, but a market with both cost-driven and demand-determining functions.