Can the development cost of the holding part be deducted from the land value-added tax of the sales part?

You can't. Property is not held for sale. According to the provisions of land value-added tax, the income and cost settlement of land value-added tax should adhere to the principle of matching. The amount of deductions should be accurately collected in each deduction. If different types of real estate are built in the same project, the proportion of deducting the project amount can be calculated according to the proportion of the actually sold land use right area to the saleable land use right area, or according to the proportion of the sold construction area to the saleable construction area.