Сделать по центру

.pstrnav { 
  height: 30px; 
  clear: left; 
  margin-top: 30px; 
  margin-bottom: 30px; 
  text-align: center; 
} 
 
.pstrnav li { 
    width: 26px; 
    height: 26px; 
    margin-left: 7px; 
    float: left; 
    margin-top: 3px; 
}

<div class="pstrnav"> 
  <ul style="display: inline-block"> 
    <li><a class="pstr-active" href="?page=1">1</a></li> 
    <li><a href="?page=2">2</a></li> 
    <li><a class="pstr-next" href="?page=2">&gt;</a></li> 
  </ul> 
</div>