The invention discloses a slope excavating and digging foundation provided with a pile anchor. A square column is inserted into a reserved cup mouth of an amplification foot, a gap between the square column and the cup mouth is filled by structural mortar, and a line tower support leg is fixed on the upper end of the square column through a foundation bolt; a cat anchor penetrates through a reserved duct above the column, a base plate and a taper hole anchor ring are sleeved on the exposed end of the cat anchor, after the cat anchor is tensioned through a jack, a clamping piece is punched into the tape hole anchor ring for wedging the cat anchor; the reserved duct is filled by the structural mortar. After the amplification foot and the excavating and digging foundation are bounded to a reinforcement cage on site, the concrete is overall cast on the amplification foot and the excavating and digging foundation, and the amplification foot and the excavating and digging foundation are buried in a bearing stratum. The slope excavating and digging foundation has the advantages of simple structure, simplicity in operation and capability of effectively improving the integrated stability of a power transmission tower footing, and improving the anti-uplifting capability and the anti-dumping capacity of the power transmission tower footing on the slope of a mountainous area with the complicated geological condition.