Hi Sachin,

You just need add param tag for delete command link as well how you have added for edit. then it will work.

VF
---------------
<apex:page controller="contactEditDelete" tabStyle="Account">
    <apex:form >
    <apex:pageBlock title="Account Detail">
        <apex:pageBlockSection >
        <apex:outputField value="{!acc.Name}"/>
        <apex:outputField value="{!acc.Phone}"/>
        <apex:outputField value="{!acc.Fax}"/>
        <apex:outputField value="{!acc.AccountNumber}"/>
        </apex:pageBlockSection>
        
       <apex:pageBlockSection title="Contact" collapsible="false" columns="1" id="pgBId">
           <apex:pageBlockTable value="{!acts}" var="conts">
               <apex:column headerValue="Action">
               <apex:commandLink value="Edit |" action="{!editRedirect}">
               <apex:param value="{!conts.Id}" name="selectedContactId" assignTo="{!selectedContact}"/>
               </apex:commandLink>
               <apex:commandLink value="Del" action="{!deleteSelectedContact}">
                   <apex:param value="{!conts.id}" assignTo="{!delContId}" name="delContId"/>
               </apex:commandLink>
               </apex:column>
               <apex:column value="{!conts.Name}"/>
               <apex:column value="{!conts.Title}"/>
               <apex:column value="{!conts.Email}"/>
           </apex:pageBlockTable>
       </apex:pageBlockSection>
        
     </apex:pageBlock>
    </apex:form>
</apex:page>

----------------------
Controller
-----------------------

public class contactEditDelete{

public Account acc {get;set;}
public String selectedContact {get;set;}
public String delContId{get;set;}
public String currentRecordId {get;set;}
public String parameterValue {get;set;}


    public contactEditDelete(){
          Id id  = ApexPages.CurrentPage().getparameters().get('id');
       acc  =  (id==null)?new Account():[select  Name,Phone,fax,AccountNumber From Account where Id =:id];
        
    }
    public List<Contact> getacts(){
          currentRecordId  = ApexPages.CurrentPage().getparameters().get('id');
          List<Contact> acts = [select id,Name,Title,Email,Phone from Contact where AccountId =: currentRecordId ];
          parameterValue = ApexPages.CurrentPage().getparameters().get('nameParam');
          return acts;
    }
         
    public PageReference editRedirect(){
    selectedContact =apexpages.currentPage().getParameters().get('selectedContactId');
    PageReference pg=new PageReference('/'+selectedContact+'/e');
    return pg;
        
    }
    
             // added action method for delete
    public PageReference deleteSelectedContact(){
     String delSelContId= ApexPages.CurrentPage().getparameters().get('delContId');
       
    if(delSelContId!=null && String.isNotEmpty(delSelContId)){
    Contact delContact = [Select Id from Contact where Id=:delSelContId];
               delete delContact;
        }
        
    return null;
    }
    
          
}

Please mark best if it helps you. Thanks in advance.

Regards,
Pawan Kumar