we have plan going to guangzhou china by land starting from macau. May i ask how many hours ?

You can take a taxi or bus from Macao to Gongbei Border. Passing the immigration, you will reach Zhuhai. Walk about 170 yards, you can reach the Gongbei Bus Station, where you can take direct buses to different areas of Guangzhou in around 130min. The bus fare is CNY75, and the bus schedule is quite dense.

Or you can walk for 0.6 miles from the border to Zhuhai Railway Station, where you can take the bullet trains to Guangzhou South. The train ride is about 1 hour, and the fare is CNY70 for the second class seat and CNY90 for the first class seat.