Implementation of Sieve of Eratosthenes in Python
Code review
Advice 1
primeslist is not used. Remove it from your code.
Advice 2
x=2: PEP 8 requires to put two spaces around the operator =.
Advice 3
Also PEP 8 complains about while (j &lt; primeseries):. Those parentheses (()) are not required; remove them in order to reduce the visual clutter.
Advice 4
The identifier primeserieslist is misspelled: it should be prime_series_list. Actually, the role of that very list is to hold the actual prime sieve, so why not rename it simply to sieve?
Advice 5
if (z &lt;= primeseries):
    if (z in primeserieslist):
        primeserieslist.remove(z)

could be written as
if z &lt;= prime_series and z in prime_series_list:
    prime_series_list.remove(z)

Advice 6
SieveofEratosthenes: in Python, CamelCase identifiers are suggested to be used for naming classes. What comes to function naming, your name should be sieve_of_eratosthenes.
Advice 7
x = x + 1: you can write more succinctly x += 1.
Advice 8
Both operations prime_series_list.remove() and z in prime_series_list run in average linear time, and, thus, are inefficient. See below for more efficient implementation.
Alternative implementation
Your implementation works and seems correct, yet there is room for improvement code style -wise and efficiency-wise:
def sieve_of_eratosthenes(max_integer):
    sieve = [True for _ in range(max_integer + 1)]
    sieve[0:1] = [False, False]
    for start in range(2, max_integer + 1):
        if sieve[start]:
            for i in range(2 * start, max_integer + 1, start):
                sieve[i] = False
    primes = []
    for i in range(2, max_integer + 1):
        if sieve[i]:
            primes.append(i)
    return primes

I have set up this benchmark. From it, I get the output:



SieveofEratosthenes in 17560 milliseconds.
sieve_of_eratosthenes in 31 milliseconds.
Algorithms agree: True



Any question? Give me a message.