An MP-1000 portable drill was used to drill a 45° inclined hole in Erdaokan village of Nenjiang County, Heilongjiang Province during survey of silver polymetallic mines. The drill occupies a small area and is easy to move, so it is suitable for inclined hole drilling. In view of drill hole leakage, collapse, falling stones, deviation in inclined hole drilling, the modified rigid cement plugging agent was used to plug the leakage section of the drill hole with good plugging effect achieved; the drilling fluid with proper wall protection performance has been selected to reduce the collapse and falling stones in the drill hole; and the anchor bolt has been adopted to fix the drill to prevent hole deviation. The high body drill bit was used to reduce the number of trips and avoid hole deviation due to squeezing drill tools by falling stones. By choosing the appropriate flushing fluid and optimizing the drilling technology, good results has been achieved in drilling of the 45° inclined hole.