Cairo - The ruling is a punishment for YouTube website that will cost it massive economic losses.
"The ruling is final, unappealable and enforceable," Xinhua quoted lawyer Mohamed Hamed Salem as saying.
A lower administrative court has previously ordered the National Telecommunications Regulatory Authority (NTRA) to do so, but the latter appealed against the ruling, citing it was hard to implement.
The top administrative court rejected the NTRA appeal on Saturday and upheld the temporary ban as a final, unappealable ruling.
The lawsuit dates back to 2013 when the Egyptian lawyer demanded to ban YouTube in Egypt until the offensive clip on anti-Islamic videos are removed.
It is unclear how the temporary ban will be implemented, as YouTube was still working in Egypt until Saturday evening.