Until recently, two major criticisms have been raised about the court’s practice of calculating employee invention remuneration. The first criticism is that in calculating the employer’s profit, it is not necessary to apply only the method of multiplying the hypothetical royalty rate, and it is necessary to apply the method of multiplying the employer’s profit rate together. The second criticism is that when calculating the employer’s profit, the calculation process of the hypothetical royalty rate, exclusivity contribution rate, and employee invention’s contribution rate, same circumstances are applied redundantly. Accordingly, this study proposes two improvement methods to address these criticisms. The first method is to calculate the employer’s profit by multiplying the employer’s sales by the employer’s profit rate, exclusivity contribution rate, and employee invention’s contribution rate. The key to this method lies in calculating the employer’s profit by multiplying the employer’s sales by the employer’s profit rate. The second method is to calculate the employer’s profit by multiplying the employer’s sales by the hypothetical royalty rate and exclusivity contribution rate. The key to this method is not to calculate the employee invention’s contribution rate to avoid duplicate application of the same circumstances as much as possible. Improvements in the principles for calculating for employee inventions remuneration can strengthen employee’s creative motivation for inventions by creating a legal environment in which employee inventions remuneration is calculated at a higher than it is currently.