by using procedure we can execute 300 step since each proc
contain max of 255 steps...

one way :

so here we may use 2 proc to execute 300 steps...

another way:

we may use one proc(255 steps) and remaining steps(45 steps)
just include in a same job after that proc

we can't execute more than 255 steps in one job, so it is 
not possible with procs also indirectly

I think its not possible.

Write a jcl like the below. Two jobs will be submitted from
the same jcl.

//JOBCARD1 .........
//STEP1 EXEC  ...
......
.....
//STEP255 EXEC ...
...
//JOBCARD2 ....
//STEP256 ..
.........

i think it might be possible by using procdure.

we have write more than 255 step by using proc.And proc 
step also included on that.

In a job max no of step is 255 ,if we want more than this 
we have  to submit one more jcl with in the same job
by using 'internal reader' its a part of JES 
ex..
// step1 exec...
.
.
.

//step255 exec pgm=IEBGENER
//sysut1 dd dsn=another jcl 
//sysut2 dd dsn= (*.INTRDER)
//sysprint dd sysout=*

one job can execute max. of 255 steps only...
so we cant execute 300 steps in one job...

we can solve this using procs...
1). we can write some steps in one proc and remaining in 
another procs call these two procs in one job then we can 
execute 300 steps.
2). we can write 255 steps in one proc and remaining steps 
in job....

call one job using another job
put all the 300 job in 2 diff job 0r jcl

give correct answers..

Hi Ravi,
   prashanth answer is correct.

Prasanth Answer is  absolutely correct