Is there any bus direct from Wuyuan to Lushan mountain? How much it cost and take how long to reach?

There is no direct bus to reach the moutain from Wuyuan directly. You need to make a transfer at Jiujiang city.
From the Wuyuan bus station, you can find two buses to reach Jiujiang and the buses are at 08:30 and 13:50. The buses take about 3 hours to reach Jiujiang Bus Station. The bus fare is around 69 to 76RMB.
From Jiujiang Bus station, you can find frequent buses to reach the mountain directly. The bus fare is around 12 to 15RMB. This bus takes about an hour.