#include <stdio.h>
#include <stdlib.h>
#define LEN sizeof(struct Date)
struct Date
{
    int num;
    int score;
    struct Date *next;
};
int n;
struct Date *creat(void)
{
    struct Date *head;
    struct Date *p1,*p2;
    p1=p2=(struct Date *)malloc(LEN);
    scanf("%d,%d",&p1->num,&p1->score);
    n=0;
    head=NULL;
    while(p1->num!=0)
    {
        n=n+1;
        if(n==0) head=p1;
        else p2->next=p1;
        p2=p1;
        p1=(struct Date *)malloc(LEN);
        scanf("%d,%d",&p1->num,&p1->score);
    }
    p2->next=NULL;
    return(head);
}

int main()
{
    struct Date *pr;
    pr=creat();
    printf("\nnum=%d\nscore=%d",pr->num,pr->score);
    return 0;
}

你的这个程序的 head  一直为null,然后你又去访问 head的元素，所以肯定会崩溃的哦