The invention provides a grab bucket, a continuous wall hydraulic grab bucket grooving machine and a grab bucket working method. The grab bucket comprises a grab bucket base, a grab bucket shell and a scraper, wherein the grab bucket shell is connected to the grab bucket base in a pivot mode, and the scraper is located in the grab bucket shell; the scraper includes a scraper body which is of a platy structure; when the grab bucket shell is in a fully open state, the scraper body is connected to the grab bucket base in a pivot mode in the form of at least covering a part of a soil inlet of the grab bucket shell, so that the scraper can rotate freely when the grab bucket grabs soil; in this way, the scraper will not cover the soil inlet of the grab bucket shell, and therefore the soil feeding amount of the grab bucket shell is not affected; furthermore, the scraper body is of the platy structure, so that the scraping area of the scraper is greatly increased when the grab bucket discharges the soil, and working efficiency of the grab bucket can be improved. Besides, in the working process of the grab bucket, the scraper can further compress ground for squeezing and draining, so that accumulated water in the grab bucket does not need to be drained by utilizing extra tools and time, the working efficiency of the grab bucket can be further improved, and the use cost of the grab bucket is saved.