1. Construction process: derrick-elastic ceiling elevation line-painting black paint above the elevation line-installing water, electricity and ventilation pipes-installing surrounding mineral wool board ceiling-initially installing metal grille-setting ceiling position and height-adjusting fire spray head height according to ceiling camber line-adjusting metal grille according to camber height. 2. Find the regularity of the plane position of the suspended ceiling: As the east-west length of each floor of the shopping mall is 120m, the north-south width is 34.7m, and the spacing between columns is 8.0m*8.0m, the vertical or parallel relationship between the metal grille and the mineral wool board, the suspended ceiling, the suspended ceiling and the walls and columns must be properly handled. Therefore, the relevant axis should be measured to the facade of the wall column, and the rules of plastering should be found according to this baseline. Use this as the benchmark for the plane position of the ceiling. 3. Form and height of arching of grid ceiling: the longitudinal dimension of this project is too long, which is not suitable for arching. The springing should be in the short north-south direction, and the springing height can be about 1/200 of 8m column spacing. 4. The plane position of the fire sprinkler should not coincide with the grille bar, and both directions should be straight. Therefore, a pedal bend greater than 900 can be made at the upper end of the fire sprinkler vertical pipe to fine-tune the plane position of the sprinkler. 5. Reservation of inspection holes for equipment: As all kinds of pipes in the grille ceiling are equipped with regulating valves, inspection holes must be reserved at corresponding positions.