two different partition how make one partition

It can be directly done as resizing and moving data are separate operations.
For managing partitions, System->Administration->Gparted is the more user friendly tool.

One solution could be:
1) Run Gparted
2) Reduce partition to remove at lowest possible size (will be checked by Gparted) & move from opposite size of other partition. It should be done in a single operation to avoid wasting time.
3) Increase target partition with space freed from other partition
4) Move your data from partition to remove to partition to keep
5) Return to Gparted
6) Delete emptied partition
7) Resize partition to keep

Another solution is to use an external drive,
1) With Gparted create an ext4 partition of same size that final partition
2) Copy all data to final partition (if you use command line, use "cp -p" to keep date and owner)
3) With Gparted, delete two previous partition, and make new one
4) Copy from external drive to new partition

DO A BACKUP OF IMPORTANT DATA

If one of these two partitions is "/" or "/home", all must be done by booting on Ubuntu CD, and choosing "Try without install".

The packet name of Gparted is "gparted".

Hi moorthy.d, firstly BACKUP any data you need before trying!

With my instructions you are going to delete 2nd partition and extend 1st one to fill all disk space.
You must run GParted from a LiveCD or LiveUSB to resize a partition already used as root, so get a LiveCD or create a LiveUSB.

Remember: there is always a possibility to loose data from 1st partition (in case of mistake), so COPY any data you need!

- boot LiveCD or LiveUSB
- run GParted (press just enter to password using Live session)
- select the drive to be changed from the pull down menu at top-right

- check the partition table and be sure that this is the disk you want to change

- right click on the second partition line and 'Unmount'
- right click again on second partition and 'Delete'
- right click on 1st partition (not the unallocated) and 'Resize/Move'
- use the ruler arrows to select 'all disk space' resulting to 0 preceding/following space
- click resize/move
- click on 'green tick mark' to 'Apply all Operations'

Regards,
George

Sorry for my 'similar answer'! Testing my instructions before posting and did not see the answer.
G

thanks to all,
my problem solved.