Aggregate demand curve is a curve reflecting the relationship between aggregate demand and price level, which inclines to the lower right, indicating that aggregate demand and price level change inversely. The interest rate effect is that the price level affects the investment through its influence on the interest rate. The main factor determining interest rate is money supply and demand. When the money demand is stable, the interest rate is mainly determined by the money supply. Money supply is the amount of money in circulation. The amount of money can be divided into nominal money and real money, and the real money supply determines the interest rate. When the nominal amount of money remains unchanged, the price rises and the real amount of money decreases; The decrease of real money leads to the increase of interest rate, which leads to the decrease of investment. Investment is an important part of total demand, so from the perspective of investment, the change direction of total demand and price level is opposite. The exchange rate effect is that the price level affects the net export through the influence on the exchange rate. One of the important factors affecting a country's exchange rate is interest rate. In the case of free capital flow, capital flows from low interest rate areas to high interest rate areas. If the interest rate of a country's currency rises, the demand for the country's currency in the foreign exchange market will increase, and the exchange rate will rise. The rise in the exchange rate reduced net exports. Net export is a part of total demand, so the influence of net export reduction, total demand reduction and price level change on total demand is expressed by moving along the same curve. The price rises and moves to the upper left along the same curve; The price falls and moves to the right along the same curve. When the price level remains unchanged, other factors change, leading to the parallel movement of aggregate demand curve. The total demand increases and the curve shifts to the right; The total demand decreases and the curve moves to the left. If consumption increases, investment increases and net exports increase, total demand will increase and aggregate demand curve will move in parallel.