Abstract: It is difficult to make a proper adjustment plan for tight oil reservoirs due to the less comprehensive economic benefit evaluation for waterflooding development of tight oil horizontal well groups. Based on a large number of analysis and research results, by taking M area of J oilfield as an example, the types of field well pattern affected by geological factors and development process are divided into perfect well pattern(O-type) and imperfect well pattern(I-type, T-type, L-type, C-type and U-type). The economic benefits of different displacement modes are evaluated by means of profit coefficient and numerical simulation. The results show that for the I-type, T-type and L-type displacement modes, when the drilling cost is less than 1.5 million per well, the profit gained by improving the well pattern is greater than the drilling cost, which is the key point of well pattern adjustment, and it can be adjusted to the perfect well pattern(O-type). For C-type and U-type displacement modes, the drilling cost of improving well pattern is higher than the benefit of increasing production, so it is suggested to mainly adjust the injection and production parameters.